If you yell "Bernanke!" when you hit your thumb with a hammer, you're probably a saver who's trying to get some income from your investments.

The Federal Reserve has been keeping short-term interest rates near zero for the past five years in a bid to revive the economy. Low rates are swell for lenders. For savers? Not so much. To get higher returns, you have to accept higher risk — which, for many investors, has meant high-yielding, low-quality, high-risk junk bonds.

How have those investors done? Quite well, actually. Even after a long period of good return from junk bonds, they can still be an appealing part of your portfolio, provided you're comfortable with the risk.

Let's start with the basics. When you lend money, the interest rate you can charge depends on two things. The first is the amount of time you're lending your money. You'd charge less for a $1,000 loan to your Uncle Joe if he's repaying you next week than if he plans to repay you in 2035. A lot can happen in 22 years: Joe could die, you could die, Joe could move to Brazil.

The other factor is Joe's creditworthiness. If Joe's idea of a steady job is selling Volkswagen parts at a jam-band concert, you'd probably want a higher rate of interest than if he were, say, a plumber. You can get good money for an old Beetle clutch, but this assumes you're not trading it for, um, other things.

The same two factors affect the yield on a high-yield bond, which is a loan to a company with a dubious credit rating. Junk bonds get their name because they don't have a credit rating high enough for many institutional investors to buy them. Junk ratings from Standard & Poor's range from BB — the top junk rating — to D, which means the bond is in default. (The more letters, and the closer to AAA, the higher the rating. A CCC-rated bond is more creditworthy than a C-rated one.)

Other factors, of course, do matter. Verizon priced its 10-year bond at about 5.19%, vs. 3% for a 10-year Treasury note, because it had a bucket load of debt to sell — $49 billion, the largest corporate bond issue ever. The bond was in the lower investment grade, but sold for a relatively high yield compared with similarly rated issues.

"They priced it real cheap," says Mark Durbiano, manager of Federated High Income Bond (ticker: FHIIX). "If you stand on a corner and give away $10 bills, it's surprising how many people will surround you."

Because interest rates have been so low for so long, junk bonds have been exceedingly popular, despite the increased risk of default. Their popularity has paid off for investors: The average junk-bond fund has gained 2.9% this year, vs. a 3.1% loss for the average intermediate-term bond fund, according to Morningstar. In the longer term, junk bonds have gained an average 9.27% a year, vs. 7.83% a year for the average large-company stock fund.

One reason high-yield funds have done well: high yields. When you're getting 6% or more in interest payments, you can absorb some shocks to your bond's price. One of the mind-numbing aspects of bond investing is that when bond prices fall, yields rise, and vice-versa. At the height of the credit crisis in 2008, when everyone thought that we'd all be living on a diet of boiled gravel, high-yield bonds yielded 22.3 percentage points above comparable Treasury bonds, mainly because their prices got flattened. Despite those high yields, the average high-yield fund lost 27% in 2008.

But like stocks, high-yield bonds fare well when the economy improves. When investors sense that a company's finances are getting better, they're willing buy that company's bonds at higher prices and lower yields. High-yield bonds tend to be more closely correlated with the stock market and the economy than with government or municipal bonds.

Currently, the Barclays High-Yield Bond index yields a bit less than five percentage points above comparable Treasuries. That translates into average yields of about 6.3%, says Todd Vandam, portfolio manager at Loomis Sayles. That's low, but Treasury rates are low. (The index more closely tracks five-year T-notes, which currently yield about 1.7%.)

That's about right, says Federated's Durbiano. "The economy is OK, autos and housing are good," he says. And, he says, investors aren't aware of how good corporate balance sheets are. "They have a lot of cash flow, and there's nothing crazy on the balance sheet side," Durbiano says.

Many companies, like homeowners, have refinanced their debt at lower interest rates, which can be an enormous cost savings. "That's helped a lot of companies in servicing debt, even with a punk economy," says Vandam.

If you're interested in junk bonds, you have several choices. Cost is always crucial: When yields are this low, even for junk bonds, you want a fund with low expenses. SPDR Barclays Capital High Yield Bond ETF (JNK – get it?) charges just 0.40% a year in expenses, and follows the Barclays High Yield Very Liquid Index.

Dan Wiener, editor of The Independent Adviser for Vanguard Investors, a newsletter, likes Aquila Three Peaks High Income fund (ATPAX), a highly conservative junk fund that doesn't soar in bull markets, but greatly reduces your terror in bear markets. "When you don't know where the economy is going, it pays to be conservative," Wiener says.

Sandy Rufenacht, the fund's manager, says that low-rated junk is extremely risky — and if you want that, you may as well be in stocks. In fact, the Aquila Three Peaks Opportunity Growth fund invests in the stocks of the same companies that issue the bonds owned by the high-yield fund. "It's a good one-two punch," Rufenacht says. The fund has outstripped the S&P 500 stock index for the past three years.

Typically, high-yield funds are less prone to rising interest rates, which drive bond prices down and yields up. "Those higher coupons are going to potentially insulate some of the negative price action of a rising rate environment," says Jennifer Vail, head of fixed income for U.S. Bank Wealth Management.

But high-yield bonds, even though attractive, aren't for anyone who can't put money at risk. "If you think there's going to be a recession or an equity market bear market, don't buy high yield," says Durbiano. "If you think the economy is OK, high yield is where you want to be. "